In certain vehicles, and more specifically in non-articulated vehicles for commercial use or for transporting passengers, such as vans or large vehicles, vehicle manoeuvrability in curve is greatly improved by means of incorporating the possibility of providing rotation to the wheels of the rear axle.
In this sense, there are various systems for steering the rear wheels of a vehicle today which allow implementing a small steering angle in order to reduce the turning radius of the vehicle. Usually said steering possibility is limited in set-off conditions from standstill and after a specific vehicle speed, respectively, for reasons of space and safety.
An example of such devices or rear wheel steering systems is described in international application no. WO-2009/156738-A1, wherein a rear wheel steering system is shown comprising an independent suspension assembly for each rear wheel, such that each assembly comprises an A-shaped suspension arm known as a trailing arm or semi-trailing arm, each assembly comprising an electric actuator which is supported by each suspension assembly, comprising a moving rod the end of which acts on the axle of each wheel, thus allowing the independent rotation of each wheel. With this device the vehicle turning radius is reduced, increasing its manoeuvrability. Additionally, said international application describes options relating to the activation of said rotation, depending on the state of a rear sliding door and on the vehicle speed, both at the start of the movement and in the case of driving at high speeds.
However, this system has two drawbacks:                it increases the non-suspended masses since the actuators are assembled on the suspension arms of the vehicle themselves, and        the wheels may move independently in the opposite directions if an actuator control system fault occurs        